Tic-Tac-Toe Solver

The Tic-Tac-Toe Solver takes any position and returns the perfect move — win, loss or draw.

Whose turn?
Options

Enter any Tic-Tac-Toe position, pick whose turn it is, and a perfect-play engine highlights the best move and tells you whether it's a win, a loss or a draw. It works as a Tic-Tac-Toe best-move calculator — recreate any board and it names the optimal next move to play. Everything runs in your browser, nothing is uploaded. See how the solver works →

How to Use the Solver

Click a square to cycle it through blank, X and O, and recreate the position on your board. Set whose turn it is, then press Solve. The best move (or moves, if several are equally good) lights up in green, and the message tells you the outcome with perfect play — a forced win, a certain loss, or a draw. Clear empties the board.

How the Solver Works

Tic-Tac-Toe is small enough to solve exactly. The engine uses minimax: it plays out every possible continuation to the end of the game, assuming both sides play perfectly, and scores each — a win, a loss or a draw — preferring faster wins and slower losses. The move that leads to the best guaranteed result is the answer. Because it searches the entire game tree, the advice is provably optimal. It all runs on your device.

The verdicts are exact, not estimated: the engine enumerates all 5,478 reachable positions and 255,168 possible games, and that full enumeration is published as an open benchmark dataset so anyone can verify the counts.

Frequently Asked Questions

How do I enter a position?
To enter a position, click a square to cycle it through blank, X and O until the board matches yours. Whose turn? follows the board as you place marks (X moves first), and you can flip it if your position differs. Then press Solve to see the best move for that player.
Does it play perfectly?
Yes — the solver plays perfectly. It searches the whole game tree with minimax, so it always finds a move that guarantees the best possible outcome: a win if one is forced, otherwise a draw. Because the board has only nine squares, that tree is small enough to search exhaustively every time.
Can Tic-Tac-Toe always be won?
No — Tic-Tac-Toe cannot always be won. Between two perfect players every game ends in a draw. A win only appears when the opponent makes a mistake, and the solver shows you exactly how to punish one and how never to make one.
What do the highlighted squares mean?
The green highlighted squares are the best moves for the side to move. Several may be highlighted at once, which means they are equally good under perfect play and you can take any of them. A square left unhighlighted leads to a worse result than the highlighted ones.
Is anything uploaded?
No — nothing you enter is uploaded. The board and the search run entirely in your browser, so no position is sent to a server. Closing the tab clears the board.
Is this a Tic-Tac-Toe best move calculator?
Yes — the Tic-Tac-Toe solver works as a best-move calculator. Recreate the current board, set whose turn it is, and it names the optimal next move for that side. Because it searches the whole game tree with minimax, the move it gives is the one that guarantees the best result, so you can use it as a next-move calculator for any Tic-Tac-Toe position.

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Prefer to play? Take on the unbeatable AI Tic-Tac-Toe. Solving other games? Try the Connect 4 Solver, the Sudoku Solver or the 2048 Solver, or browse all AI solvers & analyzers.

New to the theory? TicToe.org's guide on how to never lose at tic-tac-toe walks through the key positions this solver evaluates.

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